Apparatus and method for false twisting yarns



y 6, 1965 e. A. CARRUTHERS 3,192,697

APPARATUS AND METHOD FOR FALSE TWISTING YARNS Filed Aug. 26, 1963 2 Sheets-Sheet 1 FIG. 3

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APPARATUS AND METHOD FOR FALSE TWISTING YARNS Filed Aug. 26, 1963 2 Sheets-Sheet 2 FIG. 4

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INVENTOR United States Patent 3,1925% APPARATUS AND METEKUD FGR FALSE TWESEENG YARNS George A. Sarruihers, Harieyswiile, Pan, assignor to Turbo Machine Qompany, Laasdaie, Pa, a corporation of Pennsylvan a Filed Aug. 26, 1963, See. No. 394,523 10 Claims. (61. 57--34) This invention relates to an apparatus and method for modifying synthetic heat-settable yarn filaments. More specifically, the invention relates to the false twisting of yarn composed of synthetic material which is subject to heat-setting, and relates particularly to apparatus and method of the type disclosed in my US. Patent No. 3,- 091,908 granted June 4, 1963.

It has now been found that under certain conditions of operation, particularly at high speeds, the twisted length of yarn develops a tendency toward establishing a resonant frequency, which causes a pronounced longitudinal shifting of the point of separation of the twisted yarns. At times, this resonance can be developed to such a great extent that the longitudinal shifting and vibration of the point of separation is in excess of that which can be handled-by conical withdrawal rolls of standard size. This problem is even greater when two sets of twisted yarns are processed side-by-side since two points of separation are maintained close to one another and this presents considerable danger of tangling due to shifting of the points of separation.

Thus, it is an object of this invention to provide an apparatus and method for producing false twist type yarn with drastically increased speed and which compensates for or eliminates entirely the aforementioned disadvantages which are attributable to oscillation of the point of yarn separation due to the establishment of a resonance which is attributable either to the natural resonance of the twisted yarn length or to resonance in the yarn handling machinery, or both.

Other objects and advantages of this invention will further appear hereinafter, and in the drawings whereof:

FIG. 1 represents a top plan view showing one specific form of apparatus having utility and carrying this invention into eifect;

FIG. 2 is a view in side elevation, enlarged, showing a yarn snubbing portion of the apparatus taken as indicated by the lines and arrows I[II which appear in FIG. 1;

FIG. 3 is a view in perspective showing further details of the yarn snubbing apparatus appearing in FIG. 2;

FIG. 4 is a top plan view similar to FIG. 1 but showing a preferred form of apparatus according to this invention; and

PEG. 5 is a sectional view taken as indicated by the lines and arrows V-V which appear in FIG. 4.

The drawings and the following description of the drawings are intentionally directed to specific embodiments of the invention and are not intended to limit the scope of the invention, such being defined by the appended claims.

It will be apparent that the apparatus shown in FIG. 1 of the drawings is generally similar to that appearing in FIG. 1 of my aforementioned Patent No. 3,091,908. It will be appreciated that frame carries pairs of spaced apart feed rolls 11 for feeding separate ends of yarn Y from pirns 12, in the direction indicated by the arrows. Each yarn passes through a guide 13 and emerges from the nip between the upper and lower rolls 11. The number 14 designates separating pins for the yarns, which converge and are pretwisted to form a twisted zone T extending along a predetermined longitudinal axis. The

yarns which diverge from one another at a point of separation S, are shown in FIG. 1 as being directed to opposite sides of the longitudinal axis of the twisted Zone, each passing through the nip between an upper conical roll 15 and a lower conical roll 16 located directly beneath it. The feed rolls ll and'conical rolls 16 are driven by a motor 24, belt 25 and sprocket 26 which is secured to shaft 27. At the opposite end of shaft 27 is a bevel gear 3%) meshing with a shaft gear 31 affixed on shaft 3.2 which at its opposite end drives a belt 33'c-onnected through gears 34, 35 to flexible drive shafts 36 drivingly connected to the lower conical rolls. Thus, the conical withdrawal rolls are driven in timed relation with respect to the feed rolls 11, in a manner to maintain the yarns suspended between such sets of rolls, under a limited and predeterminable amount of tension. Preferably, the peripheral speeds at approximately the longitudinal centers of the conical rolls are equal to the pcripheral speeds of the feed rolls.

The number 37 designates a hot plate energized by wires dtl and provided with a temperature indicator 41, the plate 37 beirn in contact with the twisted yarns in a manner to heat the yarns. Hot plate 37 may also be provided with a cooling means at its exist or downstream end, thus subjecting the yarns to cooling after they have been subjected to heating. Other means may be provided for cooling yarn, such as an air pipe or the like, as shown in my aforementioned issued Patent No. 3,091,- 908.

As the apparatus is operated at exceedingly high speed, vibrations tend to cause a wandering of the point of separation S, since the yarn is substantially suspended under tension between the feed rolls and the withdrawal rolls, and is also in contact with the heating and/or cooling plate as heretofore discussed. However, it has been discovered that at certain extremely high speeds resonant conditions are sometimes encountered, causing a longitudinal vibration and oscillation of the point of separation S, which causes wide deviations of the yarns as they move toward the conical rolls. It has been discovered that the application of a frictional force downstream of the heating and/or cooling means and upstream of the point of separation S, serves to snub or damp out such excursions as are due to the development of resonant peaks, thus eliminating the tendency of the point of yarn separation to oscillate in a longitudinal direction.

One such means for effecting this result is the snubber 38 which includes a bracket 39 aifixed to the machine frame, a plate 42 mounted for pivotal adjustment about a pivot 43, and a pair of spaced apart friction members 45 which are mounted in a position for deviating the twisted yarns from their straight-line path, as appears in FIG. 2. Preferably, the friction members 45 are rods,

the upstream friction member 45 having a pair of up' wardly extendingyarn guides 44 and the downstream rod 45 having a pair of downwardly extending yarn guides 44. i

It will be appreciated that the friction member can be adjusted about its pivot in a manner to increase or to decrease the frictional force applied to the rapidly moving twisted yarn.

FIGS. 4 and 5 show a preferred form wherein two sets of pretwisted yarns are processed side-by-side, providing two points of separation S and S. Preferably the sets are pretwisted one clockwise and the other counterclockwise so that the product is a balanced yarn. Here, the pretwisted sets are separated by providing spaced parallel grooves St) in the hot plate 37, closely adjacent the snubber bars 45 which are closely adjacent the points of separation S, S. Preferably, one set of pretwisted yarns is Apparatus of the type illustrated in the drawings and just described is fully applicable to all the forms of the apparatus shown in my issued Patent No. 3,091,908, the disclosure of which is incorporated herein by reference.

While this invention has been described with reference to specific embodiments thereof, it will be apparent to those skilled in the art that various changes other than those referred to above may be made in the form of the device, that equivalent elements may be substituted for those illustrated in the drawings, that parts may be reversed, and that certain features of the invention may be used to advantage independently of the use of other features, all within the spirit and scope of the invention as defined in the appended claims.

The following is claimed:

1. Apparatus for modifying heat-settable yarn filaments comprising means for feeding a plurality of yarn sets in a downstream direction, heating means downstream of said feeding means and in a heat-setting zone through which the yarns of each set thereof pass in a twisted, tensioned condition, Withdrawal means downstream of said heating means for separating said yarns from each other and combining yarns from different sets, and combined separating and friction means located intermediate said heating means and said withdrawal means in contact with said yarn sets to divert each of said yarn sets from a straight line path of movement, and to direct said yarn sets respectively into different paths of movement.

2. The apparatus defined in claim 1 wherein the combined separating and friction means is adapted for frictionally engaging longitudinally spaced twisted portions of each yarn set.

3. Apparatus for modifying heat-settable yarn filaments comprising means for feeding a plurality of yarns twisted about each other and in a tensioned condition continuously through a heat-setting zone, driven rollers angularly arranged at opposite sides of said zone for separating said yarns from each other and withdrawing the separated yarns, and friction means located intermediate said heatsetting zone and said rollers and frictionally engaging longitudinally spaced twisted portions of the yarns and operative to divert said twisted yarns from a straight line path of movement.

4. The apparatus defined in claim 3 wherein the friction means includes a pair of laterally spaced stationary members extending across the path of the yarns.

5. The apparatus defined in claim 4 wherein each of the stationary members is provided with yarn guiding means, and the yarn guiding means respectively of said stationary members extend in opposite directions.

6. The apparatus defined in claim 4 wherein said stationary members are fixed to a common support which mounts said members for being swung about an axis extending across the path of the yarns, said members being thereby adapted for selectively determining the path of the yarns.

7. Apparatus for modifying heat-settable yarn filaments comprising separate feed means for feeding separate yarns, means for driving said feed means, means downstream of said feed means for forming an elongated twist zone in which said yarns are twisted together, heating means downstream of said feed means and in said twist zone for heating said yarn in a twisted, tensioned condition, a pair of separate withdrawal means downstream of said heating means and located at opposite sides of said elongated twist zone for separating said yarns from one another after heating and while tensioned, means for driving said withdrawal means in timed relation to the drive of said feed means, thereby maintaining said twisted yarns under tension and maintaining a floating point of yarn separation at the downstream end of said twist zone, and friction means located intermediate said heating means and said withdrawal means in contact with said twisted yarns including a pair of spaced apart stationary members positioned to cause said twisted portion to deviate from a straight-line path, each of said stationary members being provided with yarn guiding means, one extending upwardly and the other downwardly.

8. Apparatus for modifying heat-settable yarn filaments comprising separate feed means for feeding separate yarns, means for driving said feed means, means downstream of said feed means for forming an elongated twist zone in which said yarns are twisted together, heating means downstream of said feed means and in said twist zone for heating said yarn in a twisted, tensioned condition, a pair of separate withdrawal means downstream of said heating means and located at opposite sides of said elongated twist zone for separating said yarns from one another after heating and while tensioned, means for driving said withdrawal means in timed relation to the drive of said feed means, thereby maintaining said twisted yarns under tension and maintaining a floating point of yarn separation at the downstream end of said twist zone, and friction means located intermediate said heating means and said withdrawal means in contact with said twisted yarns including a pair of spaced apart stationary members positioned to cause said twisted portion to deviate from a straight-line path, said stationary members being fixed to a common support which is swingably mounted for adjustment relative to the path of said twisted portion.

9. In a method of modifying thermoplastic heat-settable yarn filaments, the steps of twisting a plurality of ends of said yarn together, tensioning them, passing them while twisted together through a heating zone maintained at a heat-setting temperature, separating the ends of yarn continuously from each other by withdrawing said yarns in different directions, and applying frictional forces to longitudinally spaced portions of said yarns, respectively on opposite sides thereof, prior to separating the same, whereby to control vibration of said yarns.

10. In a method of modifying thermoplastic heat-settable yarn filaments, the steps of twisting a plurality of ends of said yarn together, tensioning them, passing them while twisted together through a heating zone maintained at a heat-setting temperature, cooling the heat-set yarns in a twisted, tensioned condition, separating the ends of yarn continuously from each other by withdrawing said yarns in different directions, and applying frictional forces to opposite sides of said yarns respectively to longitudinally spaced portions of said yarns after cooling and prior to separating the same.

References Qited by the Examiner UNITED STATES PATENTS 1,966,440 7/34 Dickie et a1 57-157 X 2,801,455 8/57 McLellan. 2,881,504 4/59 Billion. 3,091,908 6/63 Carruthers 5734 FOREIGN PATENTS 1,082,461 6/54 France. 1,120,046 4/56 France.

815,647 7/59 Great Britain. 581,121 8/58 Italy.

MERVIN STEIN, Primary Egtqminer. 

1. APPARATUS FOR MODIFYING HEAT-SETTABLE YARN FILAMENTS COMPRISING MEANS FOR FEEDING A PLURALITY OF YARN SETS IN A DOWNSTREAM DIRECTION, HEATING MEANS DOWNSTREAM OF SAID FEEDING MEANS AND IN A HEAT-SETTING ZONE THROUGH WHICH THE YARNS OF EACH SET THEREOF PASS IN A TWISTED, TENSIONSED CONDITION, WITHDRAWAL MEANS DOWNSTREAM OF SAID HEATING MEANS FOR SEPARATING SAID YARNS FROM EACH OTHER AND COMBINING YARNS FROM DIFFERENT SETS, AND COMBINED SEPARATING AND FRICTION MEANS LOCATED INTERMEDIATE SAID HEATING MEANS AND SAID WITHDRAWAL MEANS IN CONTACT WITH SAID YARN SETS TO DIVERT EACH OF SAID YARN SETS FROM A STRAIGHT LINE PATH OF MOVEMENT, AND TO DIRECT SAID YARN SETS RESPECTIVELY INTO DIFFERENT PATHS OF MOVEMENT. 